Nokea
When comparing the types of viruses that infect bacteria, plants, and vertebrate animals, what trends appear from bacterial to vertebrate viral groups?
- A. Less complex-type forms
- B. more enveloped forms
- C. fewer enveloped forms
- D. same number of DNA-containing forms
Correct Answer: B
Rationale: The correct answer is B: more enveloped forms. This trend can be explained by the complexity of host organisms. Bacteria have simple cell structures, making enveloped viruses less common. As we move from bacteria to plants and vertebrate animals, the complexity of host cells increases, leading to a higher prevalence of enveloped viruses. This trend is due to the need for enveloped viruses to evade the host's immune system and facilitate entry into host cells. Choices A, C, and D are incorrect because they do not consider the relationship between virus structure and host complexity.
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A patient who has a large amount of carbon dioxide in the blood also has what in the blood?
- A. Large amount of carbonic acid and low hydrogen ion concentration
- B. Small amount of carbonic acid and low hydrogen ion concentration
- C. Large amount of carbonic acid and high hydrogen ion concentration
- D. Small amount of carbonic acid and high hydrogen ion concentration
Correct Answer: C
Rationale: Excess CO2 forms carbonic acid, increasing hydrogen ion concentration and lowering pH.
What is the primary function of anaphylotoxins (e.g., C3a, C4a, C5a) in the immune system?
- A. Suppressing inflammation
- B. Facilitating antigen presentation
- C. Inducing inflammation and recruiting immune cells
- D. Neutralizing pathogens
Correct Answer: C
Rationale: The correct answer is C: Inducing inflammation and recruiting immune cells. Anaphylotoxins, such as C3a, C4a, and C5a, are small molecules that are released during complement activation. They play a crucial role in enhancing inflammation by attracting immune cells to the site of infection or injury.
1. Anaphylotoxins induce inflammation by stimulating the release of histamine and other inflammatory mediators.
2. They promote vasodilation and increase vascular permeability, allowing immune cells to easily reach the affected area.
3. Anaphylotoxins also act as chemoattractants, recruiting neutrophils, macrophages, and other immune cells to the site of inflammation to help fight against pathogens.
4. These molecules do not suppress inflammation (choice A), facilitate antigen presentation (choice B), or neutralize pathogens (choice D). Their primary function is to amplify the immune response by inducing inflammation and recruiting immune cells to combat infections
Which normal tissues manifest early, acute responses to radiation therapy?
- A. Spleen and liver
- B. Kidney and nervous tissue
- C. Bone marrow and gastrointestinal (GI) mucosa
- D. Hollow organs such as the stomach and bladder
Correct Answer: C
Rationale: Bone marrow and GI mucosa are highly sensitive to radiation and show early acute responses.
What is the correct order of steps needed for 2nd generation sequencing?
- A. DNA fragmentation, DNA isolation, amplification, primer ligation, sequencing
- B. Amplification, primer ligation, sequencing, DNA fragmentation, DNA isolation
- C. DNA isolation, DNA fragmentation, primer ligation, amplification, sequencing
- D. Sequencing, DNA isolation, DNA fragmentation, primer ligation, amplification
Correct Answer: C
Rationale: The correct order of steps for 2nd generation sequencing is C: DNA isolation, DNA fragmentation, primer ligation, amplification, sequencing. Firstly, DNA isolation is crucial to extract the DNA from the sample. Next, DNA fragmentation breaks the DNA into smaller fragments for sequencing. Primer ligation involves attaching primers to the DNA fragments. Amplification is necessary to make multiple copies of the DNA fragments for sequencing. Finally, sequencing is the process of determining the nucleotide sequence of the DNA fragments. This order ensures that the DNA is properly prepared and amplified before sequencing, leading to accurate results.
Choices A, B, and D are incorrect because they do not follow the correct sequence of steps required for 2nd generation sequencing. Incorrect sequences may lead to errors in the sequencing process and inaccurate results.
To raise antibodies that interfere with the interaction of HIV with CD4+ T cells, vaccines should target which of the following HIV antigens
- A. gp41
- B. Reverse transcriptase
- C. gp120
- D. Matrix proteins
Correct Answer: C
Rationale: The correct answer is C: gp120. This is because gp120 is a key HIV antigen that plays a crucial role in binding to CD4 receptors on T cells, facilitating viral entry. By targeting gp120, vaccines can induce antibodies that block this interaction, preventing HIV from infecting CD4+ T cells. Conversely, choices A, B, and D (gp41, Reverse transcriptase, Matrix proteins) are not as effective targets for interfering with the CD4+ T cell interaction, as they do not directly impact the initial binding and entry process of HIV into the cells.